Fix weak external symbol leakage (#4758)

Summary:
This PR enforces hidden visibility for internal templates for the macOS/Linux builds. By doing so we can eliminate the weak external symbol leakage that causes linker warnings and instability in complex environments like Flask/Conda #2167.

Verified that the visibility was changed for constructors and destructors via nm -m command.

Pull Request resolved: #4758

Reviewed By: alibeklfc

Differential Revision: D90891541

Pulled By: junjieqi

fbshipit-source-id: f350c2c63745d2f005138be9eccdcaf9b2d4d0f8

Author: dascoder

faiss/python/CMakeLists.txt

@@ -114,6 +114,13 @@ swig_add_library(swigfaiss
   SOURCES swigfaiss.swig
 )
 
+if(TARGET swigfaiss)
+    set_target_properties(swigfaiss PROPERTIES
+        CXX_VISIBILITY_PRESET hidden
+        VISIBILITY_INLINES_HIDDEN ON
+    )
+endif()
+
 set_property(TARGET swigfaiss PROPERTY SWIG_COMPILE_OPTIONS -doxygen)
 
 set_property(SOURCE swigfaiss_avx2.swig